Furnace oil blast



Feb 5 1924.

C. A. GRABILL FURNACE OIL BLAST Original Filed Feb. 12. 1919 2Sheets-Sheet 1 BY I M ATTORNEY Feb. 5, 1924,;

c..'A. GRABILL FURNACE OIL BLAST Original Filed Feb. 12. 1919 2 Sheets-R Q Q Q r'-' N %Fiw B ATTORNEY Patented Feb. 5, ieaa.

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CLARENCE ALFRED GRABILL, OF EL PASO, TEXAS, ASSIGNOR TO AIlIERICANSMELT- ING & REEINING COMPANY, CORPORATION 01? NEW JERSEY.

FURNACE OIL BLAST.

Application filed February 12, 1919, Serial To all 111720-772 it mayconcern.

Be it known that I, CLARENCE ALFRED in-WILL. a citizen of the UnitedStates, and resident of El Paso. in the county of El Paso and State ofTexas, have invented certain new and useful Improvements in Furnace OilBlasts. of which the following is a specification.

The invention relates in general to an improvement in the operation of ablast furnace in certain metallurgical operations which either require,or are not deleteriously affected by. the addition of carbonaceousmaterial to the ore charge in the furnace.

As an example of one such operation it is recalled that in utilizing a.blast furnace in the smeltingof certain ores, for instance, copper ores.accumulations known as crusts, or accretions and forming artificialboshes about the inner wall of the furnace above the molten charge. Thepresence of these aocretions is objectionable and efforts have been madeto remove themby introducing carbonaceous matter, usually powdered coketogether with an air charge, into the furnace content at the base of theartificial boshes. This coke charge even when introduced into thefurnace from all sides thereof tended to move towards the center of thefusion zone and there formed an upwardly ascending combustion columnhaving little effect on the large mass of the forming accretionsadjacent the relatively cool sides of the furnace.

The invention conten'iplates the introduction into the furnace ofcarbonaceous matter but controls the admission of the same so as toprevent the formation of the boshes rather than to attempt theirdestruction after they are formed.

This result .11: attained by directing the carbonaceous n t er, togetherwith suificient air to supp rt combustion, into the furnace in the formof a series of short, hot flames co-acting within the furnace to form aring" of flame adjacent the inner wall of the furnace and at the fusionzone of the charge therein.

In. its commercially perfected form this objective is attained byatomizing liquid fuel, such as oil. just outside of the furnace interiorand injecting the same .so as to form a flame which will start at theinterior No. 276,591. Renewed September 26, 1923.

wall of the furnace but which will extend towards the center of thefurnace only for a relatively short distance.

In this way there is formed a high temperatured combustion zone close tothe portion of the wall just above the discharge ports of the usual airtuyeres and which zone does not reach to the center of the furnace.

In prior constructions where oil in liquid form was blown in through thetuyeres either with the blast or close thereto, it usually happened thatpart of the oil was not burned and ran dOwn the sides of the jacket orinto the tuyeres where it caused av great deal of trouble about thefurnaces. hen th tuyeres were opened for cleaning or barring thefurnace, oil flames projected therefrom with resulting; danger to theworkman and surrounding property.

Accordingly the invention features a construction in which the oil canbe readily vaporized so that it can be completely burned without loss infuel. and without danger to the adjacent property.

The peculiar requirements of this process necessitates a new form offurnace air tuyeres or rather a combined burner and tuyere which can useany available oil and accordingly the invention has for another objectthe providing of a burner capable of utilizing; cheap grades of crudeoil in carryinc out the above outlined process economically on a largecommercial scale.

Incidental to this last object it is a. further desidcratum to provide aburner which can be readily attached to conventional furnaces with theleast possible change in the furnaces and their associated parts, and inwhich the usual air tuyere inlets may be utilized for the introductionof the fuel while permitting, if necessary, the continuation of theiruse as entrance ports for the admission of part or even all of the airnecessary to effect the smelting or other op-. erations taking place inthe furnace.

Various other objects and. advantages of the invention will be in partobvious from an inspection of the accompanying: drawings and in partwillbe more fully set forth in the following; particular description of oneform ofmechanism embodying my invention, and the invention, alsoconsists in cerinches is suggested as outside limits.

tain new and novel features of construction and combination of partshereinafter set forth and claimed.

In the accompanying drawings:

Figure l is a view in right end elevation of afurnace looking at thesame in the direction indicated by the arrow in Figure 2, equipped witha preferred embodiment of my invention and with parts thereof brokenaway to show internal construction; and

Figure 2 is a view in side elevation of the device shown in Figure 1.

In the following description and in the claims, parts will. beindentified by specific names for convenience of expression but they areintended to be as generic in their applicalion to similar parts as the.art will permit.

In the accompanying drawings there is shown a blast furnace ofconventional form used for smelting copper ore and the like, andequipped with the usual'battery of air tuyeres 11 which are spaced apart.circumferentially of the furnace adjacent the bottom thereof anddesigned to supply air to the furnace under the usual pressure of ten tofort-y ounces per square inch.

The furnace is provided with burner receiving openings 12 which arepreferably formed. by open end tubes 13 extending through the waterjacket 14. This arrangement permits of the mounting of burners in. thetubes, so. that. the burners will be protected from the heat of thefurnace on all sides except the front. These openings are positionedabove, and preferably between, the tuyere 1 1 which arrangement has bothmechanical and metallurigicaladvantages. The distance between the levelof. thetuyeres and the level of the openings 12 will vary with the typeof furnace, the charge under treatment and other controlling factors,but a distance of six to thirty Fifteen to twenty-seven inches distancehas been used with satisfaction in one type of furnace. .Oil vaporizingburners 15 are demountably positioned in each of these openings in the:device illustrated but from four to twelve burners in active operationwill be sufiicient in the usual operations and are SOi mounted as toprevent the escape of air and oil.from the interior of the furnace.

These burners are so designed that they w1ll..atomize. the particulargrade of oil supplied 'thereto. and will produce a relativelyrshortbutintensely hot flame. The flame preferably should be-only a few inchesin lengthstarting a short distance to the outside of the inner, wall 16of the furnace and extending. into the interior furnace. onfiningthencombustion zone of burning gases to theouter side of the chargeleaves the center ofthe chargeopen to receive the air passed upwardlythrough the center of the charge from the usual tuyeres. The

oil for supplying the burners is contained in an oil tank 17 in whichthe oil is under a working pressure of 50-10O pounds per square inch.From the tank the oil is passed through one or more main pipes 18 fromwhich pipe each burner is supplied by laterally extending branch-pipesl9. Vi here the oil is too heavy to flow through the pipes without unduefriction or too heavy to be readily vaporized, it is heatedtoatemperature sufficiently high to insure an easy flow. In one instancea temperature of 225 F. has proven satisfactory with a low grade ofcrude oil at 14: Baum. The oil is heated inthie instance by means of asteam pipe (not shown) coiled inside the main oil feed tank 17 and by asteam pipe 20 encircling the main pipe 18.

The ordinary air supplied to the air tuyeres is not under sufficientpressure to satisfactorily vaporize the heavier oils and therefore theburners are supplied with air from another source under a relativelyhigh pressure. In the case above suggested a pressure of -100 pounds persquare inch has been found necessary to vaporize the heavy oileffectively. The air is supplied from a suitable source 21 and leads bysep arate branch air pipes 22 to each of the burners. In the practicaloperation of the device, the best results are obtained by supplying anamount of air to the burners insufhcient to assure the completecombustion of the amount of oil discharged per unit of time. This richfuel charge insures that the oil charge in its vaporized form will beadmitted into the interior of the furnace before it can be subjected tocomplete combustion by the air from the air tuyeres. In order to insurethis balancing of air to fuel, air metering devices 23 are positioned ineach of the branch pipes :22 and oil metering devices 2 are positionedin each of the oil branches 24. These separate controls insure anaccurate regulation of each indi vidual burner, but it is of courseobviously within the scope of this invention to control the entire oiland air supply from one metering device positioned at some convenientplace in each of the supply systems preferably adjacent the source ofthese supplies.

Referring to certain refinements of construction it may be noted thatunder some circumstances it is desirable to withdraw one or all of theburners and seal the openings as is usual infurnace practice. In orderto facilitatethe ready withdrawal of the burn ers the supply pipescontain readily separable couplings 25 which permit the burners to bewith drawnand disposed in an inoperative position. ready to be againinserted into the openings when desired.

\Vith the furnace in active operation as is usual andassuming that thereis being conducted a metallurgical process which refit.

quires the addition of fuel, it is obvious that the entire amount offuel necessary to the process may be introduced in the form of thevaporized oil from the burners. However, it has been found in practicethat bet ter results are attained by reducing the amount of coke orother usual solid fuel from 5()75% and to substitute an amount of oilnecessary to compensate for this reduc tion in the amount of coke orother solid carbonaceous material. With. the oil supply thus regulatedto give the necessary amount of fuel to the charge the oil is atomizedby the air under the relatively high pressure necessary to effect theatomization and to maintain the flame even in the presence of coolingore adjacent the inner end of the openings into the furnace. The airsupply is regulated so that it will not provide the amount of oxygennecessary to effect a complete combustion of the oil before it is fullydischarged into the interior of the furnace. In the adjustment of thesupplies to the burner, care is exercised that the flame from theburners project into the furnace but for a few inches and to form, inefiect, a substantially uniform zone or a closed circle of extremely hotflames close to the inner wall of the furnace; at the fusion zone of thecharge therein and below the point where the accretions usually begin toform in such furnaces.

The operation is continued in accordance with the usual practice as if acoke charge were introduced instead of the vaporized oil.

By means of a device of this character it is possible to maintain anintense zone of heat above the air tuyeres and close to the otherwisecool surface of the furnace and in this way the formation of accretionsis effectively prevented. Further, it is possible to economize in theuse of coke or coal which is diflicult to obtain in some locations. Theliquid oil is utilized in the device disclosed without the objectionwhich has heretofore marred the uses of liquid hydrocarbons in smeltingplants.

Having thus described my invention, I claim 1. In the operation of ablast furnace, the process which consists in forming a ring of burningcarbonaceous fuel confined to a position adjacent the inner wall of thefurnace and at the fusion zone of the charge within the furnace therebyto prevent the formation of accretions on the sides of the furnace whilepermitting a free draft up the center of the furnace interior.

2. In the art of smelting in a blast furnace, the process for preventingthe formation of accretions in the furnace, which process includes thestep of maintaining a ring of burning fuel at the place in the furnaceadjacent the place where the base portion of the accretions usually formwhen.

the furnace is operating normally and while maintaining said ring spacedfrom the vertical central axis of the furnace thereby to permit the freeentrance of air to the charge of ore under treatment in the furnace.

In the operation of a blast furnace, the process which consists indirecting a relatively short, hot flame through the side of the furnaceat the point where the base of the bushes usually appear in the usualsmelting operations and regulating said flange so that it will have alength materially less than the radius of the furnace interior.

4. In the art of smelting ores which usually require the addition of afuel such as coke, the process which consists in blowing air underrelatively low pressure through the charge as is usual with the cokecharge, reducing the amount of fuel necessary to effect the desiredoperation and supplyingthe shortage of solid fuel by introducing intothe furnace under relatively high pressure an amount of l quid fuel inatomized form sufficient to mat-t with the solid fuel present to furnishthe necessary amount of fuel said atomized fuel being of a reducingcharacter as it is passed into the furnace.

5. In the art of smelting ores, the process which consists in blowingair through the charge as usual and simultaneously causing atomizedliquid fuel to pass into the charge by means of a current of air underhigh pressure, said atomizing air current being in an amountinsuflicient to support the combustion of the liquid fuel wherebyunburned particles of fuel are conveyed to the charge there to combinewith the air in the usual blast and said air current being insufficientto project the flame of combustion of the atomized fuel to the center ofthe furnace interior.

6. In the art of smelting ores. the process which consists in forming astream of atomized oil with an amount of air insufficient to insure thecomplete combustion of the oil present and introducing said atomized oilstream into the smelting furnace adjacent the fusion zone of the orecharge therein.

7. In the art of smelting ores, the process which consists in forming astream of atomized oil with an amount of air insufficient to insure thecomplete combustion of the oil present and introducing said atomized oilstream into the smelting furnace adjacent the fusion zone of the orecharge therein and into an air stream sufficient to insure the completecombustion of the oil present.

8. In the art of smelting ores, the process which consists in forming astream of atomized oil with an amount of air insufficient to insure thecompletecombustion of the oil present and introducing said atomized oilstream into a charge of burning ore and in the presence of an amount ofair sufficient to support the combustion of both the ore charge and theoil.

9. In the art of smelting ores, the process which consists in subjectingthe charge to the action of the usual air draft having a pressure of10-t0 ounces per square inch and simultaneously injecting vaporized oilinto the furnace with air under a pressure of 50-l00 pounds per squareinch, said two air supplies cooperating to supply air to effectthedesired sineltinp operation and to support the combustion of the oil.

10. A furnace provided with an air tnyere adjacent the bottom thereofand with an opening through. the side of the furnace, spaced above saidair tuyere and at a level which will bring it adjacent the fusion zoneof the charge in the furnace and a den'iountable oil atomizing burneradapted to be inserted in said opening, said opening designed to beclosed when the burner is deniounted therefrom in the differentoperations of the furnace.

11. A furnace provided with an air tuyere adjacent the bottom thereof, aburnor above the tuyere for introducing atoniized liquid fuel into theinterior of the furnace and at a level adjacent the fusion zone of thecharge in the furnace and metering means for regulating the flame fromsaid burner thereby to produce a short, hot flame confined to a positionadjacent the inner Wall of thcfurnace and spaced from the center of thefurnace whereby the flame will be concentrated at the fusion zone of thecharge and close to the Wall of the furnace.

12. A furnace prorided with an air tuyerc adjacent the bottonr thereofand an opening into the furnace above said tuyere, an oil burnerpositioned in said opening and spaced outwardly from the inner end thereof whereby a flame may be started into the furnace interior from a pointexteriorly of the combustion zone of'the charge in the furnace and amounting for said burner for permitting the Withdrawal of the same fromthe opening.

Signed at San Luis Potosi, Mexico, this 21st day of January A. D. 1919.

CLARENCE ALFRED GRABILL.

